bool Push( Stack S, ElementType X ){
	if(S->Top == S->MaxSize){
		printf("Stack Full\n");
		return false;
	}
	S->Data[S->Top] = X;
	S->Top++;
	return true;
} 
ElementType Pop( Stack S ){
	if(S->Top == 0){
		printf("Stack Empty\n");
		return ERROR;
	}
	return S->Data[--S->Top];
}
